Growth rate–stoichiometry couplings in diverse biota

Abstract

Biological stoichiometry provides a mechanistic theory linking cellular and biochemical features of co‐evolving biota with constraints imposed by ecosystem energy and nutrient inputs. Thus, understanding variation in biomass carbon : nitrogen : phosphorus (C : N : P) stoichiometry is a major priority for integrative biology. Among various factors affecting organism stoichiometry, differences in C : P and N : P stoichiometry have been hypothesized to reflect organismal P‐content because of altered allocation to P‐rich ribosomal RNA at different growth rates (the growth rate hypothesis, GRH). We tested the GRH using data for microbes, insects, and crustaceans and we show here that growth, RNA content, and biomass P content are tightly coupled across species, during ontogeny, and under physiological P limitation. We also show, however, that this coupling is relaxed when P is not limiting for growth. The close relationship between P and RNA contents indicates that ribosomes themselves represent a biogeochemically significant repository of P in ecosystems and that allocation of P to ribosome generation is a central process in biological production in ecological systems.

N–P stoichiometry in soil and leaves of Pinus massoniana forest at different stand ages in the subtropical soil erosion area of China

“…The Masson pine forest at 13-20 years in the Green leaf N:P ratio mid-subtropics of China is in fast-growing stages and can accumulate biomass rapidly (Zhou 2001). Its high growth rate can lead to increased TP concentration, which is consistent with the previously proposed growth rate hypothesis (Sterner and Elser 2002;Elser et al 2003). Also, changes in the growth rate can alter the leaf TN concentration of the fast-growing Masson pine (Sun and Chen 2001).…”

Bottom-up effects of streambed drying on consumer performance through changes in resource quality

“…Different letters indicate significant differences (Tukey's HSD, P < 0.050) been available to detritivores fed on DRY leaves, which could have mitigated any further effects on growth. Larvae fed on DRY leaves also had a higher %P, which, consistent with the growth rate hypothesis, could be related to P-rich rRNA (Elser et al 2003), and thus, contributed to high growth rates in this treatment. The decrease in %N in DRY detritivores' body tissue, probably in response to its lower concentration in leaves, might also have contributed to the relative increase in P. Although changes in N were modest, their effects on case-building detritivores could be noteworthy (Stevens et al 2000;Mckie 2004), as the allocation of protein (silk) to case building appears to be a fixed trait (Friberg and Jacobsen 1999), and can reduce larval protein by up to 35% (Mondy et al 2011).…”

Accumulation and enhanced cycling of polyphosphate by Sargasso Sea plankton in response to low phosphorus

“…However, based on our measured C:P ratios (TWNA, 106 ± 11; Sargasso Sea, 200 ± 33) and TPP concentrations, we estimate that P-sparing strategies collectively save 13 nmol·L −1 TPP, but that phospholipid substitution accounted for only 14% of this saving (Table S1 and SI Materials and Methods). Therefore, predominant strategies for reducing cellular P probably involve DNA (e.g., "genome streamlining") (24), RNA (e.g., slower growth) (25), or other P-containing biochemicals whereas polyP cannot be spared beyond a certain extent. Indeed, polyP is intimately linked to primary metabolism in both eukaryotes and prokaryotes such that the inability to synthesize polyP results in a diverse range of cellular defects (26,27).…”